INT-836 XPath header enricher. namespace to follow

org.springframework.integration.xml/src/main/java/org/springframework/integration/xml/enricher/XPathHeaderEnricher.java

@@ -0,0 +1,108 @@
+/*
+ * Copyright 2002-2008 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.integration.xml.enricher;
+
+import org.springframework.integration.core.Message;
+import org.springframework.integration.message.MessageBuilder;
+import org.springframework.integration.transformer.Transformer;
+import org.springframework.integration.xml.DefaultXmlPayloadConverter;
+import org.springframework.integration.xml.XmlPayloadConverter;
+import org.springframework.integration.xml.xpath.XPathEvaluationType;
+import org.springframework.util.StringUtils;
+import org.springframework.xml.xpath.XPathExpression;
+import org.w3c.dom.Node;
+
+import java.util.Collections;
+import java.util.Map;
+import java.util.Set;
+
+
+/**
+ * Transformer implementation which evaluates XPath expressions against the message payload and inserts the
+ * result of the evaluation into the messsage header
+ *
+ * @author Jonas Partner
+ */
+public class XPathHeaderEnricher implements Transformer {
+
+    private final Map<String, XPathExpression> expressionMap;
+
+    private Map<String, XPathEvaluationType> evaluationTypes;
+
+    private XPathEvaluationType defaultEvaluationType = XPathEvaluationType.STRING_RESULT;
+
+    private volatile boolean skipSettingNullResults = true;
+
+    private volatile XmlPayloadConverter converter = new DefaultXmlPayloadConverter();
+
+
+    /**
+     * Create an instance of XPathHeaderEnricher using a map of the header name to the XPathExpression to evaluate
+     * All XpathExpressions are currently evaluated as returning Strings
+     *
+     * @param expressionMap
+     */
+    public XPathHeaderEnricher(Map<String, XPathExpression> expressionMap) {
+        this.expressionMap = Collections.unmodifiableMap(expressionMap);
+    }
+
+    public void setConverter(XmlPayloadConverter converter) {
+        this.converter = converter;
+    }
+
+    public void setSkipSettingNullResults(boolean skipSettingNullResults) {
+        this.skipSettingNullResults = skipSettingNullResults;
+    }
+
+    public void setEvaluationTypes(Map<String, XPathEvaluationType> evaluationTypes) {
+        this.evaluationTypes = evaluationTypes;
+    }
+
+    public void setDefaultEvaluationType(XPathEvaluationType defaultEvaluationType) {
+        this.defaultEvaluationType = defaultEvaluationType;
+    }
+
+    public Message<?> transform(Message<?> message) {
+        MessageBuilder builder = MessageBuilder.fromMessage(message);
+        Node node = this.converter.convertToNode(message.getPayload());
+
+        Set<String> keys = this.expressionMap.keySet();
+        for (String key : keys) {
+            XPathExpression expression = this.expressionMap.get(key);
+            XPathEvaluationType evalType = this.defaultEvaluationType;
+
+            if (this.evaluationTypes != null && this.evaluationTypes.containsKey(key)) {
+                evalType = this.evaluationTypes.get(key);
+            }
+
+            setHeader(node, key, expression, evalType, builder);
+        }
+        return builder.build();
+    }
+
+    protected void setHeader(Node node, String headerName, XPathExpression expression, XPathEvaluationType evaluationType, MessageBuilder builder) {
+        Object result = evaluationType.evaluateXPath(expression, node);
+
+        boolean  nullOrEmptyString = (result == null ||
+                (result instanceof String && !StringUtils.hasLength((String)result)));
+
+        if (!nullOrEmptyString || !this.skipSettingNullResults) {
+            builder.setHeader(headerName, result);
+        }
+    }
+
+}

org.springframework.integration.xml/src/main/java/org/springframework/integration/xml/xpath/XPathEvaluationType.java

@@ -0,0 +1,33 @@
+package org.springframework.integration.xml.xpath;
+
+import org.springframework.xml.xpath.XPathExpression;
+import org.w3c.dom.Node;
+
+
+/**
+ * Enumeration of different types o XPath evaluation used to indicate the type of evaluation that should be carried out
+ * using a provided XPath expression
+ */
+public enum XPathEvaluationType {
+
+    BOOLEAN_RESULT {public Object evaluateXPath(XPathExpression expression, Node node) {
+        return expression.evaluateAsBoolean(node);
+    }},
+
+    STRING_RESULT {public Object evaluateXPath(XPathExpression expression, Node node) {
+        return expression.evaluateAsString(node);
+    }},
+    NUMBER_RESULT {public Object evaluateXPath(XPathExpression expression, Node node) {
+        return expression.evaluateAsNumber(node);
+    }},
+
+    NODE_RESULT {public Object evaluateXPath(XPathExpression expression, Node node) {
+        return expression.evaluateAsNode(node);
+    }},
+    NODE_LIST_RESULT {public Object evaluateXPath(XPathExpression expression, Node node) {
+        return expression.evaluateAsNodeList(node);
+    }};
+
+    public abstract Object evaluateXPath(XPathExpression expression, Node node);
+
+}